Animator-friendly way to drive follicle pupils like an aim constraint would?

[Anonymous]

I've been trying to rig a set of cartoony eyes that are basically comprised of one giant eyeball with the surrounding face mesh shape making it look like two attached eyes (think Sonic). Since regular eye rotation can't work with this style of eyes, I've created separate mesh pupils that I've attached to the eyeball surface via follicles.

However, I can't figure out what the best way is to establish controls that drive the pupil movement along the mesh like a regular aim constraint setup would do for an eye rig. I imagine some kind of conversion from translation/rotation inputs to the parameterU/V is necessary, but I'm unsure beyond that. Any suggestions are hugely appreicated!

[zewt · Accepted solution]

This eye rig might get you started:

https://zewt.github.io/zMayaTools/tool-eye-rig.html

You'll need to create joints at the eyes, as if you were rigging a regular spherial eye, but they're just there to tell the rig where the eyes are.  Then you can use the angleLeftX, etc. outputs on the control handle.  It outputs the horizontal and vertical angles, which can be scaled and used to drive UV outputs.  It was meant to be used with 2D UV-mapped eyes (moving an eye texture around), but it should work for what you're doing too.  Just connect them to a multMatrix, so you can scale them to the range you need, then drive the UV positions with that.

The rig uses a custom plugin just for the viewport control, but if you don't want your rig to require that you can just replace the shape.  The rest is just a DG rig.  (It could probably be simplified a lot, especially with the new 2020 rigging features.)

By the way, if you can use Maya 2020, check out the new UV Pin node.  It's a much nicer and faster way of attaching a mesh to an object than follicles.

[Christoph_Schaedl]

Or create two eyes and use a lattice in the middle of the head to squeeze them.

[Anonymous]

Thank you so much!! And apologies for the very late reply!